17

Q1. Name any four useful products other than wood, which we get from forests

Solution

Four useful products which we get from forests are rubber, paper, gum, spices, etc.

Q2. (a) What is the importance of humus? (b) What happens if an animal dies in the forest? (c) Give an example of a food chain.

Solution

(a) The presence of humus ensures that the nutrients of the dead plants and animals are released into the soil. From there, these nutrients are again absorbed by the roots of the living plants. (b) The dead animals become food for vultures, crows, jackals and insects. In this way, the nutrients are recycled. (c) Grass   insects frog snake eagle

Q3. Why forests are called green lungs?

Solution

Plants release oxygen through the process of photosynthesis which helps the animals for respiration. They also maintain the balance of oxygen and carbon dioxide in the atmosphere. That is why the forests are called green lungs.

Q4. How does forest protect the planet?

Solution

1. Forests create a stable climate and help stabilize the ground and prevent erosion. 2. They protect coasts from waves and ocean swells, they stabilize sand dunes, protect the groundwater and prevent the spreading of desert. 3. Forests are very important for biological diversity.They are the habitat for up to 90% of terrestrial species of animals and plants. 4. The forest provide us with timber, firewood, oils, rubber, medicine.

Q5. Discuss how the forest is a 'dynamic living entity'?

Solution

The forest harbours a great variety of plants and this provides greater opportunities for food and habitat for the herbivores. Larger number of herbivores provides increased availability of food for a variety of carnivores. The wide variety of animals helps the forest to regenerate and grow. Decomposers help in maintaining the supply of nutrients to the growing plants in the forest. Therefore, the forest is full of life and vitality and is a dynamic living entity.

Q6. Give four examples of decomposer

Solution

Bacteria, worms, slugs, snails, fungi are some of the examples of decomposer.

Q7. (i) While walking in a forest during rains, Raju found that the raindrops were not hitting the forest floor directly. Why?(ii) How do forests reduce noise pollution?

Solution

(i) The uppermost layer of the forest canopy intercepts the flow of raindrops, and most of the water comes down through the branches and the stems of the trees. Also, rain water drips slowly from the leaves over branches of the shrubs and herbs. Hence, raindrops are not able to hit the forest floor directly.(ii) Forests absorb the noise of the activities occurring around it like sound of vehicles from nearby highway and thus helps in reducing noise pollution.

Q8. Write any three problems encountered if forests disappear.

Solution

(i) If forests disappear, the amount of carbon dioxide in air will increase, resulting in the increase of earth's average temperature. (ii) In the absence of trees and plants, the animals will not get food, protection and shelter. (iii) In the absence of trees, the soil will not hold water, which will cause floods. (iv) Deforestation will endanger our life and environment. (Any three points)

Q9. Rohan wrote a food chain the following way: Frog → Eagle → Insects → Grass → Snake The chain is not in the correct order. Help him to write the food chain correctly.

Solution

The correct way of depiction of food chain is: Grass → Insects → Frog → Snake → Eagle

Q10. How do forests help to maintain the water table?

Solution

The forests act as a natural absorber of rainwater and allows it to seep into the ground. Thus, it helps to maintain the water table throughout the year.

Q11. How do trees play an important role in regulating the climate?

Solution

Forests have a key role in regulating the climate, because trees by their photosynthesis absorb carbon dioxide from the atmosphere and store carbon as wood and organic matter in the soil.